1. Field of the Invention
The present invention relates to a portable system for secure viewing of images. The system is also capable of providing true three-dimensional imagery.
2. Description of the Related Art
The coming of the information age has lead to an increase in the development and presentation of information. Additionally, this has lead to a rise in the production of confidential, proprietary and classified information. Due to its very nature, such information must be controlled and its presentation limited to its intended audience. To date, such control has been accomplished by a variety of techniques, including for example, presentation at specially designed and secured "secure facilities." While the use of a secure facility solves the problem as only those intended to view the information are admitted, it provides little flexibility, requiring the viewer to come to it. Additionally, such facilities are quite costly, requiring special emanation control equipment and special construction techniques.
As a result of the limited success of secure facilities, a variety of secured viewing techniques have been developed. Such techniques include polarization and direct viewing, see, see Stereo Monitors Put Images in Perspective, Laser Focus World, 41, October 1989, and S. Wixson, Three-dimensional Presentations, Information Display, 24-26, July/August 1989. Both techniques are location independent in that they can be adapted to a variety of devices including portable systems. While these techniques do provide greater flexibility and lower cost, they each suffer from their own security limitations. For example, in a polarized system, a viewer is required to wear a set of polarizing glasses in order to view the image provided by a special polarized system. While a person not so equipped could not correctly see the image, a second person similarly equipped can. As for direct viewing, the viewer must be located directly in line with the viewing screen in order to see the image. While this too is better then an unprotected system, anyone located in line or directly adjacent to the viewer could see the image, or a portion of it. In addition to the security limitations, both the polarized and direct viewing systems are further limited in that they are only capable of providing two-dimensional, or at best, pseudo three-dimensional imagery to the viewer.